I've been invited by a friend to try this out, but I haven't played any shooters since CS back in the day. Tips for a new comer? How do I have a good time without bringing out the Hulk inside?
Shotguns are very strong early game. Pump shotgun can 1 hit anyone in the head whether or not they have shields. Tactical shotgun is more forgiving for misses or partial hits since it's fast rate of fire.
You want to typically drop on top of houses that have a high chance of having a chest. A chest has a guaranteed weapon and a high chance of having a better weapon you might find lying around outside of a chest, along with an additional item like bandages or shields. You'll quickly learn the spots where chests tend to spawn. They're most common found in the attic of houses. So you land on top of the house and use the pick axe to break into the attic from the roof. Chests also make a loud noise you'll learn pretty quick, and that helps identify if and where chests are when you're nearby.
Accuracy is heavily affected by movement on rifles. The single shot AR (looks like a black M16) is getting buffed on Monday-ish. The burst rifle is very strong now.
Higher rarity weapons = better aim and slightly better damage. White/grey is weakest, then it goes from green, to blue, purple, and yellow/gold is legendary.
Building is pretty key for getting around and often fighting.
Lastly, you can open your inventory by hitting i. This will let you drop items or reorganize your weapons.
Without deluging you with small tips, that is the best I can offer. Once you play with Alpha and I you'll probably learn this stuff pretty quickly anyway.